The present invention relates to an automaticaly operating apparatus for charging and/or discharging X-ray film sheets into cassettes of different formats and relates also to a cassette for use in the apparatus. The cassette is of a flat rectangular configuration and has on one of its major surfaces a bar code containing information about the cassette and film sheet format.
A charging and discharging apparatus of this kind is known for example from the German Patent No. 3,232,148. The disadvantage of this known apparatus is the relatively complex determination of the format of a cassette to be processed and of the selection of the corresponding size of the new film sheets to be inserted into the cassette. From the European patent application No. 00 79 557 it is known to provide recording foils or X-ray films with bar codes or magnetic codes located in the range of an openable window in the cassette so as to enable an automatic reading of information concerning the recording foil. In addition, from the German Patent No. 3,147,956 it is also known to apply an erasable bar code or magnetic code or electrostatic code on the cover an X-ray film cassette so as to enable the control of intended multiple exposure. However, if such prior art codes are used for indicating the format of cassettes or film sheets to be automatically processed in a film sheet charging and discharging apparatus, then a difficulty is encountered when the cassettes of different formats are fed into the apparatus. Large format cassettes whose size matches that of the intake compartment of the apparatus are advanced past a code trailer substantially parallel to the designed feeding direction and the code reader reads the coded information on the cassette without any difficulties. However, the smaller is the cassette, the greater is the possibility that for some reason or other the cassette during transportation takes an oblique position relative to the direction. Consequently, there is the probability that the code reader senses only a part of the code during the transportation of the cassette and delivers incorrect data for the automatic selection of a new film sheet to be inserted into the cassette.